In his final Oz book, Baum gives us enormous spiders, a mechanized sinking island led by a tween tyrant, and silent Mist Maidens. Each chapter of Baum's Oz books has been a fresh, light surprise. The stories are so easily entertaining, and definitely not without some thrills.
The edition I read came with an illuminating introduction and annotations by Jack Zipes, who puts things in context of the (much larger) whole of Baum's work, giving testament to the man's imagination and productivity.
Baum allowed the rules of Oz to change, but didn't forget to acknowledge that or make his characters reflect upon it. For example, the use of magic in Oz is strictly limited to the Supreme Ruler Ozma, the Sorceress Glinda, and later to the Wizard (who is brought back to Oz and favor after his flight in the first novel).
When Ozma learns that there are warring tribes in the North using magic, she and Dorothy journey to put an end to both offenses. However, once there, they find themselves trapped.
This is one of the central fascinations of Glinda: its focus on the limitations of ability and power. Even the Supreme Ruler can become stuck, not knowing how to escape a situation, and what's more, the most powerful Sorceress doesn't know how to save her. But with help, study, experimentation, patience, and a hopeful outlook (plus an unexpected coincidence), things can work out for the good.
-Michael G.